# -*- coding: utf-8 -*-#
#-------------------------------------------------------------------------------
# 建立者:        潘炎珍  
# Name:         demo14
# Description:
# Author:       98745
# Date:         2019/3/4
#-------------------------------------------------------------------------------

nl=[[1,2,3],[4,3,2],[1,2,4,5,7]]
def el(n):
    for ele in n:
        for eles in ele:
            yield eles

for num in el(nl):
    print(num,end=' ')
print()
list=list(el(nl))
print(list)
print(list[1:4])